This invention relates to rolls for feeding logs through tree handling equipment such as delimbers, tree processors and the like.
Some tree delimbers include a pair of curved knives that can be brought into contact with the outer surface of a log. The log is pulled past the knives which shear off any limbs projecting from the log. In typical tree delimbers the log is moved by compressing it between a pair of counter-rotating feed rollers. The feed rollers grip the log and move it along. An example of a tree delimber which works in this general manner is the SIDEWINDER(trademark) model delimbers available from Risley Manufacturing Ltd. of Grande Prairie, Alberta, Canada.
Some existing feed rollers are faced with spikes to enable them to better grip the outer surface of a log. These spikes can incise the outer layer of wood of the log which is undesirable.
Other commonly-used feed rollers comprise a rubber-coated cylinder having a chain mesh stretched over its outer surface. These feed rollers, while reducing damage to the log surface, suffer from relatively short service lives and can be undesirably expensive.
Commonly-owned U.S. Pat. No. 4,972,890 describes a type of feed roller which comprises a cylindrical drum having contour-edged bars bolted to its outer surface. The contour-edged bars are relatively widely spaced apart. These feed rollers have not been completely successful, because they can cause chipping of the outer surface of logs.
Despite the variety of feed rollers available for use in tree processing machinery there remains a need for feed rollers which improve on the performance and/or cost effectiveness of current feed rollers.
This invention provides feed rolls for tree handling. A feed roll provided by one aspect of the invention comprises: a substantially cylindrical drum having a longitudinal axis; a plurality of strips spaced apart around a circumference of the drum, the strips extending substantially parallel to the longitudinal axis, each strip having a leading edge and a trailing edge, each strip having projections on its leading and trailing edges, the projections on the leading edge of each strip interdigitating with projections on a trailing edge of an adjacent strip; and, a layer of resilient material between each of the strips and the drum.
Another aspect of the invention provides a feed roller for a tree handling machine, the feed roller comprising: first and second substantially circumferential rings longitudinally spaced apart from one another; a plurality of strips extending between the first and second rings, the strips each having a first end extending under an edge of the first ring and a second end extending under an end of the second ring, a leading edge and a trailing edge, the leading of each strip having longitudinally spaced apart projections interdigitating with projections on a trailing edge of an adjacent strip; and, a rotatable drum comprising a resilient surface that bears resiliently against inner faces of the strips.
Further features and aspects of the invention are described below.